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SMTP Banner Check

Discussion in 'E-mail Discussions' started by Osama Tariq, Jun 10, 2016.

  1. Osama Tariq

    Osama Tariq Well-Known Member

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    Reverse dns doesn't match SMTP banner. How can i fixed it. Moreover our SMTP Transaction Time is not good, how can i make it good ?

    By default following option is on in WHM:
    "Introduce a delay into the SMTP transaction for unknown hosts and messages detected as spam"
     
  2. Kailash1

    Kailash1 Well-Known Member

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    rDNS for your server's IP address should match to your server's hostname. If it is different, you get SMTP banner mismatch message. You can update your service provider to update rDNS for your server's IP to match it with hostname.
     
  3. Osama Tariq

    Osama Tariq Well-Known Member

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    I have my own server with same rdns and hostname of server but still gets mismatch smtp banner.
    Moreover if server has multiple ip than how other ips have same rdns ?
     
  4. Kailash1

    Kailash1 Well-Known Member

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    By default, it uses server's primary IP address to relay email. You do not need to set same rDNS for all IP and it is not at all recommended configuration. If rDNS and server hostname are same, you should not receive SMTP banner mismatch warning.
     
  5. Osama Tariq

    Osama Tariq Well-Known Member

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    But i have same rdns and hostname of primary ip of server but still shows smtp mismatch banner.
     
  6. cPanelMichael

    cPanelMichael Forums Analyst
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    Hello,

    Could you elaborate further on this? What's the specific error message you receive, and under which scenario are you receiving it?

    Thanks!
     
  7. Osama Tariq

    Osama Tariq Well-Known Member

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    When ever i put my server ip address in smtp box in this link. It shows Reverse DNS does not match SMTP Banner
     
  8. cPanelMichael

    cPanelMichael Forums Analyst
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    Hello,

    Could you verify if the issue persists when temporarily disabling the "Introduce a delay into the SMTP transaction for unknown hosts and messages detected as spam" option in "WHM >> Service Configuration >> Exim Configuration Manager >> Basic Editor"? I've seen reports that this option prevents third-party utilities such as MXToolBox from completing a check of the RDNS entry.

    Thank you.
     
  9. sawbuck

    sawbuck Well-Known Member

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    Took a long time to get here but I can confirm that turning off that option does indeed allow MXToolBox to complete the tests successfully and without errors/warnings.

    Any reason to expect that to change in the future?

    Adding the MXToolBox IP to the Trusted SMTP senders then wants to report the server is possibly an open relay. ;-)
     
    #9 sawbuck, Aug 20, 2016
    Last edited: Aug 20, 2016
  10. cPanelMichael

    cPanelMichael Forums Analyst
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    This is something you could report to the developers of those utilities, as it's an issue they would have to address with their testing behavior.

    Thank you.
     
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